| 摘要: |
| 【目的】研究干旱胁迫对番茄叶片蜡质积累的影响,及蜡质含量与蜡质合成相关基因β-酮脂酰 辅酶A合成酶（SLCER6）表达的关系，为植物表皮蜡质抗旱研究提供理论依据。【方法】以番茄品种Micro-Tom为材料，在其花蕾期进行干旱胁迫后，当植株表现出明显缺水症状时分别采集第1叶位至第7叶位的叶片，以同期正常浇水番茄植株作为对照，采用气相色谱 质谱联用仪(GC-MS)和气相色谱-火焰离子化检测仪(GC-FID)，对7个叶位叶片的蜡质成分和含量进行检测，并通过扫描电镜观察叶片的表皮超微结构，同时用实时荧光定量PCR(qRT-PCR)方法分析蜡质合成相关基因SLCER6的表达情况，最后对蜡质及其各成分含量与SLCER6基因表达量变化值之间的相关性进行了分析。【结果】(1)干旱胁迫后番茄叶片上、下表面超微结构与对照组基本一致，均没有蜡质晶体覆盖，且较为光滑，呈薄膜状结构,但皱褶明显减少，细胞凸起增多。(2)GC-MS和GC-FID分析表明，从对照组中共鉴定出24种蜡质成分，番茄叶位间蜡质含量存在一定差异，但均以烷烃含量为主，其平均含量为(1.794±0.397) μg/cm2，占蜡质总含量的93.83%，并含有少量的三萜类、初级醇和豆甾醇成分，但这３种化合物只占到蜡质总含量的4.66%。(3)干旱胁迫并没有造成番茄叶片蜡质组分以及烷烃碳链的改变，但能够极显著增加蜡质的总含量，尤其是烷烃类物质，与对照组相比，干旱胁迫组烷烃含量平均增加了161.15%，是三萜类、初级醇及豆甾醇成分总增加率的1.6倍。(4)SLCER6基因在番茄不同叶位叶片中均有表达，其表达量从第1叶位到第7叶位总体呈下降的趋势；干旱胁迫后，SLCER6基因表达量均显著增加。【结论】干旱胁迫能够极显著增加番茄叶片蜡质总含量，增加的成分主要是烷烃；干旱胁迫也能够诱导SLCER6基因表达量上调；番茄叶片蜡质积累与SLCER6基因表达量之间存在着正相关关系。 |
| 关键词: 番茄 干旱胁迫 表皮蜡质 β-酮脂酰 辅酶A合成酶基因 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金项目(31471568)；陕西省重点科技创新团队计划项目(2014KCT-25)；西北农林科技大学唐仲英育种基金资助项目 |
|
| Effect of drought stress on wax accumulation in leaves of tomato (Lycopersicon esculentum) |
|
WU Hongqi,LUO Wenqiao,ZHAO Shuai,et al
|
| Abstract: |
| 【Objective】Effect of drought stress on leaf wax accumulation and relationship between wax accumulation and SLCER6 expression in tomato were studied to provide basis for analyzing drought resistant function of plant cuticular wax. 【Method】Leaves of tomato variety ‘Micro Tom’ under drought stress at the bud stage were used as the materials.When tomato plants emerged water starved symptoms,all leaves in the first to seventh leaf positions were sampled. Taking adequate water supplied tomato plants as control,contents and components of cuticular wax in leaves were analyzed by GC-MS and GC-FID.The leaf ultrastructure was also observed by scanning electron microscopy.Expression analysis of SLCER6 related to cuticular wax biosynthesis in leaves was done by qRT-PCR method and correlation analysis among total wax and its compounds with SLCER6 expression was analyzed. 【Result】(1) The upper and lower surfaces of tomato leaves after drought stress were same as control.They were even and smooth without visible wax crystals,but had less fold and more cells bulge compared with the control.(2) A total of 24 wax compounds were identified in control by GC-MS and GC-FID. Though wax contents were different among leaf positions, alkanes were main component with average content of (1.794±0.397) μg/cm2 and contribution of 93.83% to total wax.Triterpenoids,primary alcohol and stigmasterol accounted for only 4.66% of total wax.(3) Drought stress did not cause change in wax components and alkane carbon chain distribution. However,it significantly increased leaf wax content. Especially alkanes content was increased by 161.15% averagely,which was 1.6 times of the total of triterpenoids,primary alcohol and stigmasterol. (4) SLCER6 expression was detected in all leaf positions with a declining trend from the first to the seventh leaf position.They were increased significantly by drought stress. 【Conclusion】Drought stress could significantly increase wax content in tomato leaf,especially the content of alkanes.SLCER6 expression was increased by drought stress and accumulation of cuticular wax was positively associated with SLCER6expression. |
| Key words: tomato drought stress cuticular wax SLCER6 |
